Since learning Smalltalk at KTH in around 1994 - we used VisualWorks 1.0 IIRC - I have been deeply in love with both the language, its mindset and the community with all its diversity. During many years I was very active in the Squeak community and I have also been using Pharo for various development tasks.
Today in 2014 I would say Pharo is the leading open source Smalltalk dialect, sharing lots of resources with its ancestor, Squeak, especially the Cog VM that enables Pharo and Squeak to still be competitive alternatives. At 3DICC we are using Squeak 4.x for Terf itself, both client and server. And we use Pharo for some internal tools.
The elegance of Smalltalk, through its careful design and its very powerful toolset - still today makes it a compelling tool for many tasks. The Design Principles Behind Smalltalk-article from Byte magazine 1981 is a must read for anyone seriously interested in programming languages.
Good Design: A system should be built with a minimum set of unchangeable parts; those parts should be as general as possible; and all parts of the system should be held in a uniform framework.